Docker – Running Gitlab CI runner with Docker on OS X as service

I finally figured out a solution that works.

For the problem of not showing the environment variables I refer to this: https://bz.apache.org/bugzilla/show_bug.cgi?id=37848 The gitlab-runner has no tty, so no output is shown.

The cause of the malfunctioning start is the following: Looking into the source code of the gitlab-runner you can find this: https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/blob/master/executors/shell/executor_shell.go#L84

Basically as soon as the gitlab-runner finishes it kills all its remaining processes. That means in my case the server was actually running for a short amount of time before the process got killed. That's why I got empty log files.

I solved the problem by simply writing an init script to start and shutdown tomcat. The tomcat now has its own user (and group). Now the tomcat process tree is initiated by /sbin/init. Now gitlab-runner is not aware of this process anymore or not able to kill it. Either way the tomcat keeps running after the runner stops.

Ok so after diving into docker more deeply, I understood that I have to link the runner-container to the GitLab container with "link".

This is something that is missing in the docs above. Although it says that running Gitlab and a runner on the same machine isn't suggested (which I guess would also solve the problem), in some scenarios it is needed, so it would be nice to mention that the containers have to be linked:

$ docker run -d -P --name gitlabce gitlab/gitlab-ce:latest
$ docker run -d -P --name runner --link gitlabce:gitlabce gitlab/gitlab-runner:latest

$ docker exec -it runner gitlab-runner register
Running in system-mode.                                                                                                                                                                                                                                       

Please enter the gitlab-ci coordinator URL (e.g. https://gitlab.com/):                                                                                                                                                                                        
http://gitlabce  

Please enter the gitlab-ci token for this runner:                                                                                                                                                                                                             
(your token from gitlab->admin->runner) 

Please enter the gitlab-ci description for this runner:                                                                                                                                                                                                       
[a11fa3f389d9]:    

Please enter the gitlab-ci tags for this runner (comma separated):                                                                                                                                                                                            

Registering runner... succeeded                

I'm new to docker so sorry for this trivial question, but maybe it will help others.

Another method would be to create a user defined network, since, if I understood correctly, containers can communicate with each other without links.